Abstract: This invention provides an improved process for producing azetidinones. More particularly, this invention provides the steps of producing an azetidinone represented by the formula I ##STR1## from a carboxylic acid R.sup.2 --D--CH.sub.2 COOH, an aldehyde R.sup.1 --A--CHO and an amine RNH.sub.2, by the steps of: (a) converting a carboxylic acid to the corresponding acid chloride; (b) deprotonating a chiral oxazolidinone and treating the resulting anion with the product of step (a); (c) enolizing the product of step (b) and condensing with an imine; and (d) cyclizing the product of step (c). Steps (c) and (d) of this process are as shown in the following reaction scheme.

Abstract: Novel .beta.-lactam monomers bearing various functional groups are prepared. The novel .beta.-lactam monomers can be joined into oligomeric compounds such as via preferred phosphate linkages including phosphodiester and phosphorothioate linkages. Useful functional groups include nucleobases as well as polar groups, hydrophobic groups, ionic groups, aromatic groups and/or groups that participate in hydrogen bonding. The oligomeric compounds are useful as diagnostic and research reagents.

Abstract: .beta.-lactam compounds which are reacted with a metal alkoxide for preparing N-acyl, N-sulfonyl and phosphoryl substituted isoserine esters.

Abstract: A fused benzeneoxyacetic acid derivative of the formula: ##STR1## wherein ##STR2## is (i) ##STR3## (ii) ##STR4## (iii) ##STR5## or (iv) ##STR6## A is (i) ##STR7## or (ii) ##STR8## R.sup.1 is hydrogen or C.sub.1-4 alkyl; R.sup.2 is hydrogen, C.sub.1-6 alkyl or phenyl;R.sup.3 is(i) C.sub.1-15 alkyl,(ii) C.sub.1-8 alkyl substituted by one or two of benzene, C.sub.4-7 cycloalkane or 4-7 ring-membered monocyclic ring which contains one nitrogen atom or(iii) C.sub.10-15 condensed tricyclic ring;e is 3-5;f is 1-3;p is 0-4;q is 0-2;s is 0-3With the proviso that, ring(s) in R.sup.3 may be substituted by one to three of C.sub.1-4 alkyl, .sub.1-4 alkoxy, halogen atom, nitro or trihalomethyl. And, when D--B is the formula (iii) or (iv), --(CH2)p- or .dbd.CH--(CH2)s- is attached at the position of a or b on the ring.

Abstract: The invention provides 1,3,4 substituted and bicyclic derivatives of 2-azetidinones and processes therefor. These compounds are valuable intermediates useful in the preparation of 1-carba(dethia)cephalosporin antibiotics.

Abstract: Novel cis compound having the formula: ##STR1## wherein R.sup.1 is alkyl, haloalkyl, cycloalkyl, aryl or a carbohydrate derivative; X is O, N, S, C(O)O or a direct bond; and R.sup.2 is aryl, substituted aryl or heteroaryl are useful in the synthesis of taxol and taxol derivatives.

Abstract: New substituted azetidinones of the general formula (I) which have been found to be potent elastase inhibitors and thereby useful anti-inflammatory and antidegenerative agents are described.

Abstract: A process for preparing a single enantiomer of a 4-aryloxyazetidin-2-one derivative in optically pure form comprises reacting a hindered vinyl ester with chlorosulphonyl isocyanate; displacing the hindered acyloxy group with a phenolic derivative containing a protected carboxy group; deprotecting the carboxylate moiety; resolving with a chiral amine; filtering; and regenerating the desired enantiomer by acidification. A method for enriching the product obtained from the acyloxy displacement step in favour of the desired enantiomeric form, by treating with an asymmetric catalyst such as a chiral alkaloid derivative, is provided; as also is a method for racemising the unwanted antipode of the desired 4-aryloxyazetidin-2-one enantiomer. The invention further provides novel enantiomers based on the 4-aryloxyazetidin-2-one ring structure.

Abstract: The present invention relates to new 3-guanidinoalkyl-2-azetidinones of the formula ##STR1## wherein: U and W can be the same or different and are selected from the group consisting of hydrogen and an amino protecting group;n is 1 to 3;X is a member selected from the group consisting of hydrogen, trialkylsilyl, arylsulfonyl, amino substituted arylsulfonyl, alkylsulfonyl, arylaminocarbonyl, alkylcarbonyl and arylcarbonyl; andY is a member selected from the group consisting of hydrogen, arylalkenyl, arylalkyl, formyl, carboxy, alkoxycarbonyl, acyloxy, arylthio, arylsulfinyl, arylsulfonyl, alkylthio, alkylsulfinyl, alkylsulfonyl, arylaminocarbonyl, the radical ##STR2## in which R is hydrogen, alkyl or arylalkyl, and the radical ##STR3## in which m is 1 to 3 and R' is hydrogen or --CO.sub.2 R" wherein R" is hydrogen, alkyl or arylalkyl.The novel azetidinones of the present invention exhibit anti-thrombin and anti-trypsin activities and are thus useful in controlling blood coagulation and treating pancreatitis.

Abstract: Provided is a process for diastereoselectively preparing compounds of the formula ##STR1## which includes the step of subjecting a compound of the formula ##STR2## to a salt whose anion is a nucleophilic base whose conjugate acid has a pKa in the range of between about -7 to about 14, or a silylated derivative of the salt; whereinR.sub.1 is said nucleophile;R is hydrogen, or protected amino,R.sub.2 is R.sub.4 as defined herein below;R.sub.3 is a leaving group; andR.sub.4 is hydrogen, C.sub.1 -C.sub.6 alkyl, or a group of the formula--CH.sub.2 --CH.sub.2 --R.sub.6whereinR.sub.6 is 2-furyl, naphthyl, phenyl, phenyl substituted with 1, 2 or 3 substituents selected from C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.6 alkoxy, C.sub.1 -C.sub.6 alkylthio, nitro, halo, carboxy and amido; orR.sub.6 is a group of the formula--COOR.sub.7or--COSR.sub.7in whichR.sub.7 is selected from C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl, benzyl, phenyl, or benzyl or phenyl substituted with 1, 2 or 3 substituents selected from C.sub.

Abstract: Disclosed are .beta.-lactams of formula I ##STR1## wherein X is a chromogenic or fluorogenic substituted aryl or heteroaryl, which are specific inhibitors of Human leukocyte elastase (HLE). Upon contact with HLE these compounds are cleaved to form a chromogenic or fluorogenic species which may be readily measured by the assay disclosed herein. The assay thus provides a means for direct measurement of the amount of active HLE in a body fluid or other sample.

Abstract: New substituted azetidinones of the general formula (A') which have been found to be potent elastase inhibitors and thereby useful anti-inflammatory and antidegenerative agents are described.

Abstract: The present invention relates to new 3-guanidinoalkyl-2-azetidinones of the formula ##STR1## wherein: U and W can be the same or different and are selected from the group consisting of hydrogen and an amino protecting group;n is 1 to 3;X is a member selected from the group consisting of hydrogen, trialkylsilyl, arylsulfonyl, amino substituted arylsulfonyl, alkylsulfonyl, arylaminocarbonyl, alkylcarbonyl and arylcarbonyl; andY is a member selected from the group consisting of hydrogen, arylalkenyl, arylalkyl, formyl, carboxy, alkoxycarbonyl, acyloxy, arylthio, arylsulfinyl, arylsulfonyl, alkylthio, alkylsulfinyl, alkylsulfonyl, arylaminocarbonyl, the radical ##STR2## in which R is hydrogen, alkyl or arylalkyl, and the radical ##STR3## in which m is 1 to 3 and R' is hydrogen or --CO.sub.2 R" wherein R" is hydrogen, alkyl or arylalkyl.The novel azetidinones of the present invention exhibit anti-thrombin and anti-trypsin activities and are thus useful in controlling blood coagulation and treating pancreatitis.

Abstract: The present invention provides a process for protecting an amino group in a compound exposed to nucleophilic reaction conditions in which the imido group used for protection is reacted with a secondary amine to form an acyl group which protects the amino group during exposure to the nucleophilic reaction conditions, after which the acylamino group may be reacted with an acid to reform the imido group so that the compound may then undergo non-nucleophilic manipulations. Also provided is a resolution method in which diasteriometric compounds having the acylamino group as described above are reacted with acid, and as these diasteriomers react at different rates to form the imido group, the reaction may be monitored so as to isolate the desired product at the appropriate point to maximize optical purity.

Abstract: New substituted azetidinones of the general formula (A), which have been found to be potent elastase inhibitors and thereby useful as anti-inflammatory and antidegenerative agents, are described.

Abstract: New substituted azetidinones of the general formula (A), which have been found to be potent elastase inhibitors and thereby useful as anti-inflammatory and antidegenerative agents, are described.

Abstract: Compounds of the structural formulae ##STR1## and their pharmaceutically acceptable salts, esters and amide derivatives, in which R.sup.1 and R.sup.2, independently of one another, denote hydrogen or pharmaceutically acceptable groups which have 1 to 10 carbon atoms and are bonded to the remaining part of the molecule via carbon-carbon single bonds, and in which R.sup.3, R.sup.4 and R.sup.5, independently of one another, denote pharmaceutically acceptable groups which have 1 to 10 carbon atoms and are bonded to the remaining part of the molecule via carbon-carbon single bonds, are useful antibiotics.The trisubstitution by three groups R.sup.3, R.sup.4 and R.sup.5, which are bonded via carbon-carbon single bonds, results in a noticeable increase in the hydrolysis stability and thus also in the antibacterial action of axapenemcarboxylic acids.

Abstract: The present invention relates to new 3-guanidinoalkyl-2-azetidinones of the formula ##STR1## wherein: U and W can be the same or different and are selected from the group consisting of hydrogen and an amino protecting group;n is 1 to 3;X is a member selected from the group consisting of hydrogen, trialkylsilyl, arylsulfonyl, amino substituted arylsulfonyl, alkylsulfonyl, arylaminocarbonyl, alkylcarbonyl and arylcarbonyl; andY is a member selected from the group consisting of hydrogen, arylalkenyl, arylalkyl, formyl, carboxy, alkoxycarbonyl, acyloxy, arylthio, arylsulfinyl, arylsulfonyl, alkylthio, alkylsulfinyl, alkylsulfonyl, arylaminocarbonyl, the radical ##STR2## in which R is hydrogen, alkyl or arylalkyl, and the radical ##STR3## in which m is 1 to 3 and R' is hydrogen or --CO.sub.2 R" wherein R" is hydrogen, alkyl or arylalkyl.The novel azetidinones of the present invention exhibit anti-thrombin and anti-trypsin activities and are thus useful in controlling blood coagulation and treating pancreatitis.

Abstract: Compounds having the formula ##STR1## and pharmaceutically acceptable salts thereof and possessing antibacterial activiy, and intermediates to compounds of formula I having the formula ##STR2##

Abstract: A method for preparing 2-amino-.beta.-lactams which are substituted by readily-removed protecting groups is provided. According to this invention, an acyl-2-amino-.beta.-lactam is further acylated with a different acyl group and is subsequently treated with base to provide a protected 2-amino .beta.-lactam with allyloxycarbonyl, t-butoxycarbonyl, naphthyloxycarbonyl, trichloroethyloxycarbonyl, p-nitrobenzyloxycarbonyl, benzhydryloxycarbonyl, p-methoxybenzyloxycarbonyl, or o-nitrobenzyloxycarbonyl.

Abstract: An improved process for making compounds having the formula ##STR1## includes subjecting an intermediate of the formula ##STR2## to hydrogenolysis in the presence of a ketonic solvent so as to simultaneously remove both Z-protecting groups from compound II while selectively reprotecting the --A.sub.1 --NH.sub.

Abstract: This invention provides novel azetidinone intermediates having the formulas: ##STR1## wherein R.sup.1 is hydrogen, or a conventional hydroxy-protecting groups; R.sup.2, R.sup.4, and R.sup.5 are independently selected from the group consisting of hydrogen; substituted and unsubstituted: alkyl, alkenyl, and alkynyl having from 1-10 carbon atoms; cycloalkyl, cycloalkylalkyl, and alkylcycloalkyl having 3-6 carbon atoms in the cycloalkyl ring and 1-6 carbon atoms in the alkyl moieties; spirocycloalkyl having 3-6 carbon atoms; phenyl; aralkyl, aralkenyl, and aralkynyl wherein the aryl moiety is phenyl and the aliphatic portion has 1-6 carbon atoms; or various heterocyclic moieties; and R.sup.6 is methanesulfonyl or p-toluenesulfonyl; which are useful in the preparation of carbapenem antibiotics.

Abstract: Componds having the formula ##STR1## and pharmaceutically acceptable salts thereof, exhibit antibacterial activity wherein R is ##STR2##

Abstract: Compounds having the formula ##STR1## and pharmaceutically acceptable salts thereof and possessing antibacterial activity, and intermediates to compounds of formula I having the formula

Abstract: Antibacterial activity is exhibited by 2-azetidinones having a 3-acylamino substituent and having an activating group in the 1-position of the formula ##STR1## wherein R.sub.4 is ##STR2## wherein A.sub.1 is a single bond, ##STR3## --NH-- or ##STR4## A.sub.2 is a single bond, --NH--, --CH.sub.2 --CH.sub.2 --NH-- or ##STR5## A.sub.3 is a single bond, --CH.dbd.CH--, --(CH.sub.2).sub.t --, --NH--(CH.sub.2).sub.p -- or ##STR6## wherein t is 1, 2, 3 or 4 and p is 0 or 1; and A.sub.4 is a single bond --CH.sub.2 --, --NH--CH.sub.2 --, or --N.dbd.CH--.

Abstract: The invention relates to new 2-oxoazetidines having the formulas ##STR1## where R.sub.1 stands for a lower fluoroalkyl or an optionally protected lower hydroxyalkyl group; R.sub.2 for chlorine, bromine, iodine, fluorine, an ##STR2## group in which n is 0, 1 or 2 and R.sub.5 is a lower alkyl, lower alkenyl, an optionally substituted benzyl group, optionally substituted phenyl group, a --CH.sub.2 COX group in which X means a lower alkyl, lower alkoxy or the amino group, or a ##STR3## group in which Y and Z are the same or different and in each case stand for oxygen, nitrogen or sulphur and R.sub.6 stands for a lower alkyl, lower alkoxy, lower alkylthio, lower dialkylamino, an aryl, aryloxy or arylthio group, or for a group having the formula ##STR4## where W stands for --CH.sub.2 CH.sub.2 --, --CH.dbd.CH-- or C.sub.6 H.sub.4 ; R.sub.3 stands for bromine, chlorine, iodine, SeC.sub.6 H.sub.5 or SC.sub.6 H.sub.5 ; and R.sub.4 stands for hydrogen, a group having the formula ##STR5## in which R.sub.

Abstract: Compounds of the formula: ##STR1## wherein R.sup.1 is lower alkyl of 1 to 6 carbon atoms lower alkenyl of 2 to 6 carbon atoms or benzyl; R.sup.2 is lower alkoxy of 1 to 6 carbon atoms, benzyloxy or the group ##STR2## where R.sup.4 is lower alkoxy of 1 to 4 carbon atoms; and R.sup.3 is hydrogen, lower alkyl of 1 to 6 carbon atoms, lower alkyl of 1 to 6 carbon atoms substituted with 1 to 3 trihalomethyl groups, lower haloalkyl of 1 to 6 carbon atoms substituted with 1 to 6 halogen atoms, lower alkenyl of 2 to 6 carbon atoms, arylalkyl of 7 to 12 carbon atoms, lower alkoxyalkyl of 2 to 6 carbon atoms, lower alkylthioalkyl of 2 to 6 carbon atoms, or lower cycloalkyl of 3 to 8 carbon atoms are active as plant growth regulators. Certain of these compounds also show activity as selective herbicides.

Abstract: There is disclosed a process for producing carbapenam diazo intermediates of the formula ##STR1## wherein R.sup.1 is hydrogen or a hydroxy-protecting group,R.sup.2 is a lower alkyl having from 1-6 carbon atoms, andR.sup.3 represents a conventional carboxyl-protecting group.The processs comprises alkylating a 4-substituted azetidinone with the tin enolate of an .alpha.-bromoketone, in the presence of a silver salt, iodine, or iodine salt as a catalyst, and a strongly polar solvent. The .beta./.alpha. yield of the product diazo intermediate is approximately 3/1.

Abstract: A stereospecific process for preparing 3-trans-R-trisubstituted silyloxyethyl substituted azetidinones useful as intermediates for preparing penems and carbapenems is provided wherein a 3-unsubstituted azetidinone is treated with a strong base and a trisubstituted silylmethyl ketone to form 3-trans-S-[1-trisubstituted silyl-1-hydroxy]ethylazetidinone followed by rearrangement of this resulting carbinol by treatment with an alkali metal alkoxide and a proton source.

Abstract: The novel compounds of the formula ##STR1## wherein R.sup.11 signifies hydrogen, acyl or tri(lower alkyl)silyl, R.sup.2 signifies a phenyl group which is substituted in the o- and/or the p-position by halogen, lower alkyl, lower alkylthio or lower alkoxy and n signifies the number 0 or 2, and mixtures thereof with the corresponding optical antipodes are valuable intermediates for the manufacture of antimicrobially active penems and carbapenems which have as a common structural element a (R)-1-hydroxyethyl group in the 6-position. They can be manufactured by reacting a compound of the formula ##STR2## wherein R.sup.12 signifies acyl, tri(lower alkyl)silyl or a group of the formula --BR.sup.3 R.sup.4 and R.sup.3 and R.sup.4 have the same significance and each signify a branched-open chain, cyclic or bicyclic hydrocarbon residue with 5-10 carbon atoms or together signify an open chain or cyclic hydrocarbon residue with 5-10 carbon atoms and two free valencies and R.sup.

Abstract: Antibacterial activity is exhibited by .beta.

Abstract: Antibacterial activity is exhibited by 3-acylamino-2-oxoazetidines having in the 1-position an activating group of the formula ##STR1## wherein R is ##STR2## and R.sub.

Abstract: Intermediate compounds of the formula ##STR1## for the preparation of antibacterially active penem compounds and salts wherein R is hydrogen or an esterifying group, R.sup.1 is an unsubstituted or a mono-, di-, or tri-substituted phenyl, naphthyl, thienyl, pyridyl, quinolyl or isoquinolyl, R.sup.2 is hydrogen or a hydroxyl group which may be protected, R.sup.4 is chlorine or bromine and R.sup.5 is an alkyl or phenyl group; methods for making such compounds or salts.

Abstract: Antibacterial activity is exhibited by 2-azetidinones having a 3-acylamino substituted and having an activating group in the 1-position of the formula ##STR1## wherein A.sub.1 is a single bond, ##STR2## and A.sub.

Abstract: The invention encompasses a process for stereoselective carbon-carbon bond formation at C-4 position of a 3-(acylamino)azetidinone. The process is carried out under free radical conditions using a (2-substituted or unsubstituted allyl)tin reagent. Also encompassed by the invention are certain 4-(substituted selenyl)azetidinone starting materials and the corresponding 4-(2'-substituted or unsubstituted allyl)-azetidinone products.

Abstract: Antibacterial activity is exhibited by 2-azetidinones having a 3-acylamino substituent and having an activating group in the 1-position of the formula ##STR1## wherein R is ##STR2## A.sub.1 is --NH-- or ##STR3## A.sub.2 is ##STR4## or --CH.dbd.CH--.

Abstract: Antibacterial activity is exhibited by 2-azetidinones having a 3-acylamino substituent and having an activating group in the 1-position of the formula ##STR1##

Abstract: Certain 2-substituted-2-penem-3-carboxylic acid compounds and pharmaceutically-acceptable salts thereof can be prepared from the appropriate xanthate or trithiocarbonate by desulfurization and addition of an electrophilic sulfur compound followed by halogenation and ring closure. The corresponding desulfurized and halogenated olefinic intermediates are disclosed.

Abstract: The invention relates to benzopyrrolobenzodiazepines and quinobenzodiazepines of the formula ##STR1## where X and Y may be the same or different and each is hydrogen, halogen, CF.sub.3, lower alkyl, lower alkoxy, lower alkylthio and lower alkylsulfonyl, p and q are independently 1 or 2; R.sub.1 is hydrogen when R.sub.2 is bonded to R.sub.3 to form a --(CH.sub.2).sub.m --CH.sub.2 -- group or a --CH.dbd.CH-- group; R.sub.3 is hydrogen when R.sub.1 is bonded to R.sub.2 to form a --(CH.sub.2).sub.m --CH.sub.2 -- group or a --CH.dbd.CH-- group; m is 1 or 2; R.sub.4 is NR.sub.5 R.sub.6 wherein R.sub.5 is hydrogen or lower alkyl and R.sub.6 is hydrogen, lower alkyl or a group of the formula (CH.sub.2).sub.n NR.sub.7 R.sub.8 wherein R.sub.7 and R.sub.8 are lower alkyl, and n is 2 or 3, ##STR2## wherein R.sub.9 is lower alkyl, ##STR3## wherein R.sub.10 is CH.sub.2 CH.sub.2 OH, lower alkyl, phenyl, phenyl substituted by halogen, CF.sub.

Abstract: Antibacterial activity is exhibited by 2-azetidinones having an acylamino substituent in the 3-position and having an activating group in the 1-position of the formula ##STR1##

Abstract: Substituted azetidinone compounds are provided which have the formula: ##STR1## wherein one of R.sup.1 and R.sup.2 represents a substituted lower alkyl group, an azido group, an amino group, a lower acylamino group, a mercapto group or a lower alkylthio group and the other represents a hydrogen group, or, both represent hydrogen atoms or lower alkyl groups; R.sup.3 represents a hydrogen atom or a group shown by formula: ##STR2## (wherein X represents ##STR3## (wherein R.sup.5 represents a hydrogen atom or a lower alkyl group) and Y represents a hydroxy group, a lower alkoxy group, an amino group, a mono- or di-lower alkylamino group); R.sup.4 represents a hydrogen atom, a substituted or unsubstituted lower alkyl group or a group shown by formula: --CH.sub.2 CO--A (wherein A represents an amino group or a group shown by formula: ##STR4## (wherein X and Y are as defined above), provided that when R.sup.1 and R.sup.2 are both hydrogen atoms, at least R.sup.

Abstract: New substituted azetidinones are found to be potent elastase inhibitors and thereby useful anti-inflammatory/antidegenerative agents.

Abstract: Antibacterial activity is exhibited by compounds having the formula ##STR1## and salts thereof, wherein R.sub.1 is acyl;R.sub.2 is hydrogen or methoxy;R.sub.3 and R.sub.4 are the same or different and each is hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, aryl or a 5,6 or 7-membered heterocycle or one of R.sub.3 and R.sub.4 is hydrogen and the other is azido, halomethyl, dihalomethyl, trihalomethyl, alkoxycarbonyl, 2-phenylethenyl, 2-phenylethynyl, carboxyl, ##STR2## X.sub.1 is azido, amino, hydroxy, alkanoylamino, alkylsulfonyloxy, arylsulfonyloxy, aryl, cyano, --S--X.sub.2 or --O--X.sub.2 ;X.sub.2 is alkyl, substituted alkyl, aryl, arylalkyl, alkanoyl, substituted alkanoyl, arylcarbonyl or heteroarylcarbonyl;one of X.sub.3 and X.sub.4 is hydrogen and the other is hydrogen or alkyl, or X.sub.3 and X.sub.4 when taken together with the carbon atom to which they are attached from a cycloalkyl group;X.sub.

Abstract: Described is a novel process for the preparation of penams and penems useful as antibacterial agents, which comprises the reaction of an appropriate 4-substituted-azetidin-2-one with a base, followed by reaction of the thereby formed penam compound with an oxidating agent and a organic or inorganic base.Also described are novel penam compounds useful as antibacterials which are prepared by the described process.

Abstract: Compounds of the formula: ##STR1## wherein R.sup.1 is lower alkyl or benzyl; R.sup.2 is lower alkoxy, benzyloxy or the group ##STR2## where R.sup.3 is lower alkoxy; Ar is phenyl or phenyl substituted with 1 to 3 substituents independently selected from halogen, trihalomethyl, nitro, phenyl, lower alkoxy and lower alkyl; and X.sup.1 and X.sup.2 are independently hydrogen, halogen, lower alkoxy, or lower alkyl, or X.sup.1 and X.sup.2 taken together form an aromatic ring fused with the phenyl ring, provided that both X.sup.1 and X.sup.2 are not hydrogen show activity as plant growth regulators.

Abstract: Certain substituted-2-penem-3-carboxylic acid compounds, and pharmaceutically-acceptable salts thereof, can be prepared from the appropriate xanthate or trithiocarbonate by desulfurization, followed by halogenation and ring closure. The corresponding desulfurized and halogenated intermediates are disclosed.

Abstract: There are disclosed 2(N-heterocyclyl) penems and their pharmaceutically acceptable salts and esters and their use as anti-bacterials.

Abstract: A process for the preparation of a 7-acylamino-3-hydroxy-2-cephem-4-carboxylic acid, 7-acylamino-3-hydroxy-1-dethia-1-oxa-3-cephem-4-carboxylic acid or derivative thereof of the general formula ##STR1## in which R.sup.1 is hydrogen or optionally substituted alkyl, alkenyl, alkinyl, aralkyl, aryl, heteroaryl, heteroaralkyl, aryloxyalkyl, heteroaryloxyalkyl, alkoxyalkyl, arylthioalkyl, heteroarylthioalkyl, alkylthioalkyl, alkoxy, aryloxy, alkylthio or arylthio,R.sup.2 is hydrogen, a carboxy-protective group or a pharmaceutically useful ester radical, andX is sulphur or oxygen,which comprises:(a) reacting a compound of the formula ##STR2## with (i) a compound of the formula ##STR3## in which R.sup.2 and X have the abovementioned meaning and Y represents diazo (N.sub.2) or hydrogen (H.sub.2) in an inert solvent in the presence of a Lewis acid or proton acid catalyst, or(ii) a compound of the formulaHX--CH.sub.2 --C.tbd.C--COOR.sup.

Abstract: This invention relates to 2-(N-heterocycloaliphaticthio)penems wherein the nitrogen of the heterocyclic ring is connected to the alkyl group, and to their use as antibacterial agents.